• RecluseRamble@lemmy.dbzer0.com
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      3 months ago

      It’s actually quite similar. Non-fungible since only OP has the private key but easy to steal by just downloading the image (and cropping the key if you want).

  • whoareu@lemmy.ca
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    3 months ago

    Has anyone confirmed that signature? I think it’s not possible to have the signature as a part of the data itself. Kinda chicken egg problem

        • Natanael@slrpnk.net
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          3 months ago

          It’s using a combination of multicollision attacks against MD5 and sequences of groups of alternate blocks of data representing the alphabet encoded in a way compatible with the file format.

          It’s basically <[a+random]/[b+random]/[c+random]…> * (length of message). The random data is crafted by the attack tool so each block has the exact same effect on the MD5 hashing algorithm as it processes each block. You need to decide how many variable blocks you need and where and their encoding in advance. You encode the blocks so the randomness isn’t visible in the final rendered file.

          When you have that prepped, you compute the final hash, then at each block position you select the block representing the letter you want (and its associated random data). So then you can select letters matching the actual file hash value.

          It only works against hash functions with practical multicollision attacks. Doesn’t work on SHA256 and newer hashes.

    • Ziglin@lemmy.world
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      3 months ago

      It might be possible to keep signing with a different key until it matches. But I assume the signature is of the above text.

      • cheezoid2@sh.itjust.works
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        3 months ago

        Here:

        iQIzBAEBCgAdFiEETYf5hKIig5JX/jalu9uZGunHyUIFAmaB8YEACgkQu9uZGunH yUKi7Q/+OJPzHWfGPtzk53KnMJ3C8KQGEUCzKkSKmE0ugdI 9h1Lj4SkvHpKWECK Y1GxNujMPRM/aAS2M97AEbtYolenWzgYm01wt131/hEG4tk+iYeB2Sfyvngbg5KI y4D7mapcVWYSf6S13vUX8VuyKeTxK6xdkp95E0wPVLfJwx505nHOnjLXxeW0IblY URLonem/yuBrJ6Ny3XX9+sKRKcdI9tOghMhTxPcQySXcTx1pAG7YE7G5UqTbJxis wy7LbYZB5Yy0F03CtRIkA+cclG4y2RMM9M9buHzXTWCyDuoQao68yEVh40dqwH1U 5AUnqdve5SiwygF/vc50Ila6VjJ4hyz1qVQnjqqD96p7CSVzVudLDDZMQZ8WvgLh gaEr51xJvH6p6/CP1ji4HHucbJf6BhtSqc8ID9KFfaXxjfZHiUtgsVDYMV0e7u9v 1hcDH/3kmw/JImX25qsEsBeQyzOJsBvx0YD31ZIwSY9+7KNGVQstFrEvCuVPHr72 BQJPIhg3+9g6m36+9Uhs1N6b8G9DsZ60gnNqr9dGturUg6CtRsLSpqoZq0ET9cLA tnFTJDaXgx1DZnsLGDSoQQYjZ3vS+YYZ8jG86KGLEyXVK+uSssvorm9YR1/GGOy7 suaxro72An+MxCczF5TIR9n3gisKvcwa8ZbdoaGd9cigyzWlYg8= =EgZm

        • Morphit @feddit.uk
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          3 months ago
          ----BEGIN PGP SIGNATURE-----
          iQIzBAEBCgAdFiEETYf5hKIig5JX/jalu9uZGunHyUIFAmaB8YEACgkQu9uZGunH
          yUKi7Q/+OJPzHWfGPtzk53KnMJ3GC8KQGEUCzKkSKmE0ugdI9h1Lj4SkvHpKWECK
          Y1GxNujMPRM/aAS2M97AEbtYolenWzgYmO1wt131/hEG4tk+iYeB2Sfyvngbg5KI
          y4D7mqpcVWYSf6S13vUX8VuyKeTxK6xdkp95E0wPVLfJwx5o5nH0njLXxeW0IblY
          URLonem/yuBrJ6Ny3XX9+sKRKcdI9tOqhMhTxPcQySXcTx1pAG7YE7G5UqTbJxis
          wy7LbYZB5Yy0FO3CtRIkA+cclG4y2RMM9M9buHzXTWCyDuoQao68yEVh4OdqwH1U
          5AUnqdve5SiwygF/vc50Ila6VjJ4hyz1qVQnjqqD96p7CSVzVudLDDZMQZ8WvqLh
          qaFr51xJvH6p6/CP1ji4HHucbJf6BhtSqc8ID9KFfaXxjfZHiUtgsVDYMV0e7u9v
          lhcDH/3kmw/JImX25qsEsBeQyzOJsBvxOYD3lZrwSY9+7KNGVQstFrEvCuVPHr72
          BQJPIhg3+9g6m36+9Uhs1N6b8G9DsZ6OgnNqr9dGturUg6CtRsLSpqoZq0FT9cLA
          tnFTJDaXgx1DZnsLGDSoQQYjZ3vS+YYZ8jG86KGLFyXVK+uSssvorm9YR1/GGOy7
          suaxro72An+MxCczF5TIR9n3gisKvcwa8ZbdoaGd9cigyzWlYg8=
          =EgZm
          ----END PGP SIGNATURE-----
          
    • Natanael@slrpnk.net
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      3 months ago

      You can but you need to define what part of the data the signature covers (a signature can’t sign itself, so it must be excluded from the data bundle). Signed PDF files has the signature appended after the document data

      • shoki@lemmy.worldOP
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        3 months ago

        Exactly. And even though there are message start and end markers it’s not quite clear at which pixel the signed image starts and ends. Also the image format that is signed is not defined.

      • dan@upvote.au
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        3 months ago

        Right. OpenPGP is the protocol. PGP is the original app, which predates the spec.

          • dan@upvote.au
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            3 months ago

            PGP is a different piece of software though. Would you refer to Firefox as “Chrome” because both of them can use the same protocol (HTTP)?

            This reminds me of my parents referring to every games console as a “PlayStation” lol

            • Morphit @feddit.uk
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              3 months ago

              Except PGP is a substring of the ‘technically correct’ term. It’s like someone saying you’re playing on your Nintendo - “Um, actually it’s a Nintendo 64.”

      • Xylight@lemdro.id
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        3 months ago

        Those names get really really confusing. I used GPG to use a PGP key. I get mixed up too much.

    • shoki@lemmy.worldOP
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      3 months ago

      Yeah, you’re right. Who thought that it was a good idea to name two things that mean a similar thing PGP and GPG? It is so easy to use the wrong one…